Nanoindentation is an increasingly used tool to investigate the mechanical properties of very small volumes of material. Gold single crystals were chosen as a model system for surface modification studies, because of the electrochemical advantages and the simple structure of the material. Experiments on these samples displayed a spectrum of residual deformation, with measured hardness values on the same surface differing by over a factor of two. The yield point also exhibited considerable variation, but the depth of penetration was independent of this elastic–plastic transition. The onset of plastic deformation in these tests is observed at stress levels on the order of the theoretical yield strength. There are a limited number of defects in a single crystal specimen of gold, especially on the length scale required to influence nearly every indentation experiment. A test matrix was designed to change the concentrations of possible defects in a sample (dislocations, vacancies, and structural features), by altering some of the surface preparation parameters. The results of these experiments were extremely consistent. Observed trends within the matrix, combined with the observations of reduced hardness and earlier plasticity when compared to the preliminary testing, indicate a decline in the structural continuity of the sample. This is surprising considering the extensive material removal and thermal history of some of these surfaces. There is no indication of a cause for the dramatic inconsistencies in mechanical properties observed in preliminary testing, but a consistent surface enables the study of intentional modifications. Changes in contact area that were undetectable in preliminary results now demonstrate predictable shifts in hardness values. The deposition of a single monolayer of gold oxide raised the average load at yield by a factor of three and increased the hardness by over 26%. Attributing this change to the oxide is corroborated by the reduction of hardness when the oxide is stripped. Similar behavior is observed when a lead monolayer is deposited and tested ex-situ. It is surprising that layers <0.5 nm in thickness would have such a dramatic influence on indentation tests at least 35 nm deep. This indicates that no surface layer can be ignored at this scale. These experiments demonstrate that there is still much to be learned about nanoscale deformation mechanisms. / Ph. D.

The purpose of this dissertation was to determine the usefulness of the linguistic processes of Distortion, Deletion, Generalization, and Semantic Ill-Formedness as constructs which differentiate the verbal communication of families who express dissatisfaction with their current intrafamilial relationships from families expressing satisfaction with their current relationships. Specifically, it was hypothesized that dissatisfied families would use these linguistic structures to a greater extent in their interaction than would satisfied families. Thirty-one family triads (father, mother, and child) were obtained by asking families randomly selected from the local high school student directory to participate. The families were given a Revealed Differences questionnaire which they subsequently discussed together and a questionnaire regarding their satisfaction with their intrafamilial relationships. The discussions were recorded and transcribed. Each of 150 Surface Structures (a complete thought, usually a grammatical sentence) per family was scored for 11 subcategories of Distortion, Deletion, Generalization, and Semantic Ill-Formedness. Interrater reliabilities ranged from .86 to .98. A mean was computed for the questionnaire pertaining to satisfaction with family relationships. Six families who scored at least one half standard deviation below the mean comprised the "dissatisfied" family group, and six families who scored at least one half standard deviation above the mean comprised the "satisfied" family group. It was found that the dissatisfied families used significantly more Deletion (p The linguistic process of Deletion is theorized to result in impoverishing the speaker's model of the world and the behavioral choices available to the speaker. Similarily, the listener(s) who must respond to the impoverished model is limited in his response and behavioral options. Since all members of the dissatisfied families used this form of language, they perpetuate the impoverishing model of the world and the limitations on their behavior. It was concluded that, while not establishing an etiologic link between the use of Deletion and family dissatisfaction, Deletion is part of the current verbal interaction of families who express dissatisfaction. Further research involving families in which a member is symptomatic is warranted based on the findings of this study. Language may provide at least one form of explanation regarding the process by which families maintain homeostasis in the face of symptom development. The use of linguistic concepts shows promise as an intermediate link in family interaction theory as well as a form of intervention available to therapists.

Micro Hall probe magnetometry has been used to investigate the magnetisation of various electrodeposited microcrystals. Superconducting tin crystals of almost perfect square cuboid shapes exhibit a strong size dependence of the supercooling of the superconducting state and, for the smallest accessible crystals, the crossover to the mesoscopic regime can be readily explored close to their critical temperatures. Experimental results are in good agreement with Ginzburg-Landau simulations using the exact experimental parameters. Electroplating of the tin cores with another material provides unique core-shell structures of either two superconductors (S-S’: tin-lead) or of a superconducting core, covered with a ferromagnetic shell (S-F: tin/lead-nickel). The critical parameters of the tin core in Sn-Pb core-shell crystals are considerably enhanced and superconductivity in the tin core is detected up to 1:16 TSn c . Little-Parks oscillations in the shell can be analysed to reveal the extent of the superconducting sheath and hence can be utilised to measure the range of the proximity effect close to the critical temperature of the shell. In S-F core-shell structures, field cancellation effects govern the overall behaviour. Under certain conditions it was possible to switch the overall magnetic response from para(ferro-)magnetic to diamagnetic and back at finite applied fields. Micromagnetic simulations qualitatively reproduce the experimentally observed effects. Applications for the core-shell structures include magnetic guidance or memory devices.

Diamond-liked carbon (DLC) film is an important material and has many application in industry. Recently doping impurity into the DLC to change the properties of DLC thin film is a research topic attracted scientists. In this thesis, DLC films were deposited by plasma-enhanced chemical vapor deposition (PECVD) on the Si wafer and glass. Acetylene was used as the source of carbon, and nitrogen was doped in DLC need too dopants of grow N2 and NH3. The growth mechanism and differences of the nitrogen doped DLC films were studied by methods of NK measurement, SEM and nano indentation. The analysis of nano indentation showed that the hardness and Young¡¦s Module decreased with increasing N2 flow rate. However, for increased NH3 a flow rate, the hardness and Young¡¦s Module of DLC were increased. The characteristic peaks of nitrogen doped DLC in the FTIR transmittance spectra were studied, sp2 C=H bond(2945 cm-1), sp3 C-H bond(2910 cm-1), and also the C¡ÝN (2200cm-1)and C=N bond(1625cm-1) are observed in DLC. The results of FTIR shows nitrogen was doped into DLC successfully. The DLC thin films thickness was determined by the NK analysis, and it is found the deposition rate of DLC was increased with the increasing flow rate of N2. However, for increased NH3 flow rate, the DLC deposition rate was decreased. From SEM, micrographs the NH3 doped DLC yielded rough morphology. The surface of N2 doped DLC thin film, revealed smoother. A growth mechanism of diamond with different dopant was proposed and explained the properties of DLC thin film with different deposition condition.When N2 was used as dopant source, the N2+ ions were induced by plasma and attracted upward due to the RF self-bias voltage. Therefore ,the surface of thin film was not bombarded due to N2+ ions. On contrast, when the NH3 was used as dopant source, the NH2- ions were produced and distracted downward by the RF self-bias voltage. And then the surface of the thin film was etched by the NH2- ions. Form the XPS analysis, the composition of sp3 C-C(285.4 eV) and sp3 C-N (287.7 eV)were decreased with increased N2 flow rate.However, the composition of sp3 C-C and SP3 C-N were increased with decreasing the NH3 flow rate. The composition of nitrogen in the DLC film increased with higher N2 flow rate. The number of sp2 bond was increased and the hardness was decreased with higher amount of nitrogen in the DLC film. This result is consistent with the nano indentation,FTIR analysis and explained by the ionic transportation growth mechanism model.

This dissertation is focused on understanding heterogeneous bimetallic catalysts using model catalyst systems, such as Pd-Au/Mo(110), Pd/Au(111) and Pd/Au(100). Monometallic and bimetallic model catalysts, composed of Pd and Au, were prepared by physical vapor deposition (PVD) onto well-characterized metal substrates. Subsequent characterization was performed using an arsenal of modern surface science tools: low energy ion scattering spectroscopy (LEISS), infrared absorption spectroscopy (IRAS), temperature programmed desorption (TPD), and x-ray photoelectron spectroscopy (XPS). Electronic, morphological, and chemical properties of the prepared model catalysts were compared to those observed from monometallic single-crystal model catalysts such as Cu(100), Pd(111), Au(100), and Au(111). Between 700 K and 1000 K, formation of stable alloy surfaces of Pd-Au mixtures on Mo(110) was accompanied by substantial enrichment in Au. Annealing a 1:1 Pd-Au mixture at 800 K yields a Pd0.2Au0.8 surface alloy; the concentration of isolated Pd sites in this surface alloy can be systematically controlled by a judicious selection of initial bulk Pd-Au concentration. Pd-Au catalysts supported on Au(111) and Au(100) substrates generated a surface ensemble of Pd monomers surrounded by Au after annealing the systems at or above 550 K. To test the activity and selectivity of the prepared bimetallic model catalysts, the formation rate of vinyl acetate monomer (VAM) was examined. More significant enhancement of VAM formation rate was observed for bimetallic catalysts supported on Au(100) compared to those on Au(111). A critical surface ensemble composed two non-contiguous Pd monomers was proposed for the VAM synthesis. Oxygen plays a critical role in the efficiency of the synthetic route. Structure-reactivity correlations were established based on the suggested elementary reactions leading to the oxidative coupling of ethylene and acetic acid to form VAM.

The question raised in this study is: Why are similar companies so different? That is, why do companies of the same size, in the same line of business, and with the same organizational structures, etc., function in different ways? The answer to these questions is expected to be found through knowledge of basic ideas in companies. Important points of departure are that small companies are interesting research objects and that an organization can be viewed as a set of deep and surface structures which may appear in the language of its members and other interested parties. Based chiefly on deep interviews, the study is intended to generate knowledge and understanding of basic ideas and their function in small companies. The deep structures of the four companies show that the basic ideas can be understood as ideologies. They refer to basic values, are apprehended by the members of the organization and other interested parties, and prescribe what is desirable. The differences between the cases form the basis of a classification of the ideologies into four ideal types: capitalistic, religious, narcissistic, and socialistic. The surface structures are viewed in two perspectives, one referring to the behaviour of the companies and the other to the relational behaviour between the companies and the interested parties. The former shows that the patterns of behaviour are different in the four companies and may be characterized as efficiency-directed, adaptation-directed, ego-directed, and socially-directed. A comparison between these patterns of behaviour and the ideologies of the companies makes the directing function of the ideologies visible. Through situation interpretation, ideologies direct organizational behaviour towards particular patterns. The relational perspective causes the controlling function of ideologies to appear. Differences in co-acting between the companies - that is, the extent to which and on what grounds the interested parties behave in accordance with the behaviour of the companies and the attitudes of the interested parties to the ideological values - show that ideologies can exercise control either through their power over problem interpretation or their power over acting. The results of this study indicate that the answer to the initial question is that organizations have different ideological faces. / digitalisering@umu

No description available.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 170-201).

In this thesis three studies of the geometric structure of the (110) surface of single crystal rutile TiO2 are presented. Firstly, quantitative low energy electron diffraction (LEED-IV) data acquired from TiO2(110)(1x1) are reanalysed to confirm the integrity of the previously reported optimized geometries by performing structural optimisation as a function of depth into the selvedge. The second study addresses the geometry of the x-linked (1x2) reconstruction of the same surface. Again, LEED-IV data are analysed to quantitatively determine the surface structure. Part of this effort involved substantial development of the code (SATLEED) employed for simulating the experimental data, to allow simultaneous optimisation of more than one surface termination. In contrast to recent scanning probe work, the analysis indicates that the surface consists of two differently relaxed Ti2O3 added rows. The last study concerns ab initio calculations of the structure of benzoate on TiO2(110)(1x1). Of particular interest is the impact of surface coverage on the orientation of the benzene ring. It is predicted that the benzene ring twists and tilts away from high symmetry with increasing coverage due to adsorbate-adsorbate interactions. No evidence is found to support the formation of benzoate dimers or trimers, as was concluded in earlier experimental work.

This thesis deals with the combined ultra-high vacuum (UHV) and electrochemical (EC) studies of selected iron oxide surfaces, namely Fe3O4(001) and -Fe2O3(012). The state-of- the-art knowledge regarding these surfaces is briefly reviewed, and importance of understanding these materials in the electrochemical environment is discussed. The design of the transfer system between UHV and EC environment is presented; individual features of the system are thoroughly discussed and the system is used for testing the stability of the Fe3O4(001) (2×2)R45° surface reconstruction in ambient conditions. The experimental results presented in this thesis show that the Fe3O4(001) (2×2)R45° reconstruction, utilized as an adatom array for single atom catalysis studies, survives both exposure to air and to liquid water, if the exposure is achieved in well-controlled fashion. Further, this thesis presents the first-ever atomic scale scanning tunneling microscopy (STM) study of the -Fe2O3(012) surface, which is important for photoelectrochemical water splitting. STM images of two surface reconstructions of the -Fe2O3(012) surface known to date are presented. A bulk terminated model of the (1×1) reconstruction is confirmed and a novel surface structure model for the (2×1) reconstructed surface is proposed. Adsorption studies of H2O and O2 on the (2×1) reconstructed surface are documented by timelapse STM.